A Facile and Direct Glycosidation Method for the Synthesis of 2-Deoxy alpha-Rhamnosides Catalyzed by Ferric Chloride

摘要

abstract_textpA facile and highly efficient O-glycosylation method for stereoselective synthesis of 2,6-dideoxy-O-glycosides has been described promoted by FeCl3, an eco-friendly, easily available and non-toxic catalyst. Acetylated 2-deoxy rhamnoside was chosen as the glycosyl donor for its convenient preparation and great stability at room temperature. The glycosylation was amenable to a wide range of acceptors including primary, secondary, tertiary alcohols, sterols, amino acid derivatives and sugar derivatives. Thus, 2,6-dideoxyglycosides and oligosaccharides were obtained in short reaction time (40 min) at room temperature in good to excellent yields (70-97) with preponderant alpha-selectivity (alpha/beta= 4:1 to 19:1)./p/abstract_text